Many minority populations in the US have a markedly increased risk of obesity and its comorbid conditions, such as type 2 diabetes, hypertension, and cardiovascular disease, that contribute to substantially greater mortality. Much evidence suggests that the predictive risk factors and the therapeutic approaches for these comorbid conditions that are derived from the study of Caucasians may be less applicable to those of differing ethnicity or race. Effective prevention and treatment of these disorders requires a better understanding of their etiology. This unit investigates the genetic, physiologic, metabolic, and behavioral factors involved in determining weight regulation and body composition, with a special emphasis on pediatric and minority populations. Progress has been made in our longitudinal studies of body composition, energy expenditure, insulin sensitivity and glucose disposal, which seek to characterize the timing and nature of factors that may contribute to the prevalence of obesity and its complications. In the last year, we initiated treatment studies for pediatric and adolescent obesity, validated a new methodology for determination of body composition, and studied seasonality of weight gain. These studies will aid in the rational development of approaches for the prevention and treatment of obesity